A Clojure function that prints the “fully expanded form before evaluation”?

Question

Is there a Clojure function that does for any function what macroexpand-all does for a macro?

In SICP, Abelson & Sussman give a demonstration of this that they call the “linear recursive process”.

In other words, if we give:

(factorial 6)

the function would print (and not evaluate):

(* 6 (* 5 (* 4 (* 3 (* 2 (1))))))

Essentially, I am trying to “see” the data structure any function “builds up” prior to evaluation.

---

I think this would be an interesting way for beginners (myself) to see what the Reader* is building up just before it passes things on to the Evaluator*.

*Not sure I’m using the right terms here.

Answer 1

Function tracing can be done without programming. It is, for example, available in the Cider extension to Emacs. https://docs.cider.mx/cider/debugging/tracing.html

I have loaded my factorial program into Emacs, and placed my cursor on the factorial function.

 (ns factorial.core
    (:gen-class))

 (defn factorial [n]
    (if (zero? n)
     1
     (* n (factorial (dec n)))))

 (defn -main
    "A factorial program."
    [& args]

    (let [n 6] 
       (println "The factorial of " n "is" (factorial n))))

             M-x cider-jack-in

 REPL:  (in-ns 'factorial.core)

             C-c M-t v, select factorial when prompted

        (factorial 3)